1. Field of the Invention
The invention relates to a locking system for panels with edge profiles provided on at least two opposite edges of the panels for the positive connection of similar panels, including an edge profile designed as a groove profile, with an upper groove wall and a lower groove wall, and an edge profile designed as a tongue profile, with a notch projection on the underside of the tongue that engages a notch recess in the lower groove wall of an adjacent panel in the assembled state, where the engaged edge profiles form an articulated joint that acts to restore the panels to their installation plane when deflected either up or down. The invention also relates to a panel with the locking system according to the invention.
2. Background of the Prior Art
Locking systems of this kind are used for floor panels, for example, such as parquet panels with a natural wood surface or laminated panels. The latter have a core made of MDF, HDF, or particle board and are provided with a reproduced surface made of a decorative laminate.
299 11 462 U1 discloses a generic locking system, whose connection has the function of an articulated joint. Locking systems of this kind are used for floor coverings, which, for example, lie on uneven bases or must bear deflection in the connection area due to the presence a soft backing, such as impact sound insulation. Deflection of the connection causes high stresses in the region of the tongue-and-groove profiles of two locked panels, because the connection bends under the load. The panel material cannot withstand the high stresses in the region of the edge profiles and fails in the connection area.
The ease of installation of the known jointed locking system leaves much to be desired. Its resistance to being pulled apart in the installation plane does not meet expected, future quality standards for floor coverings with mechanical locking systems. Furthermore, the known joint connection can be installed in two ways, where the second installation method described is associated with the undesirable side effect that the connection displays particularly low resistance to being pulled apart.
According to the first installation method, a new panel, preferably tongue-first, is placed at an angle against a laid panel and then folded or rotated downwards until it lies in the common installation plane of the panels and locks automatically.
In the second installation method, locking occurs when both panels are in the installation plane, namely by sliding the panels laterally towards one another. The panels can only be joined together in this way because the undercut between the notch projection of the tongue and the notch recess in the lower groove wall is designed to be correspondingly small. The notch connection achieved in this way is of such low strength that gaps can form between abutting surfaces of adjacent panels due to normal changes in length of the floor. This is the case, for example, when the temperature of the floor fluctuates. This method of jointing also results in immediate damage to the edge profiles, because they must be subjected to strong deformation in order for the undercut of the tongue and the lower groove wall to engage.
Furthermore, the tongue of the known locking system has a long, tapered shape. The top of the tongue has an inclined surface that is intended to facilitate insertion of the tongue tip into the groove. In reality, however, the tongue proves to be very easily damaged due to its tapered shape. This has a disadvantageous effect on the product's ease of installation, service life, and utility.